Billy vs Liv: which is better as a dual-purpose vibrator?

I'm trying to decide which is better for use both vaginally and anally. Besides the stopper that prevents the Billy going too far anally, are there any other differences? Is the Liv safe for vaginal use?

Either is safe for vaginal use. I have used Liv anally. II don't think it's a huge safety issue, personally. They also sell toy accessories that are silicone rings you put around dildos, so you could use one of them. The Picobong Zizo is good too and waterproof.